Apparatus and method of balancing input power from multiple sources

Abstract

A scheme is provided for dynamically adjusting an amount of power drawn from individual power sources to optimize the power usage without violating power limits. Coarse adjustment is provided through dynamic phase reallocation while a fine adjustment is provided through dynamic current steering. By adding a control loop around current steering techniques in digital voltage regulator controllers, power drawn from multiple input rails is balanced. The apparatus allows users to maximize the power delivered to discrete graphics cards without violating PCIe specifications. This allows maximum performance with minimal bill-of-material (BOM) cost.

What is claimed is: 
     
       1. An apparatus comprising:
 a first power supply rail to provide a first power supply as input to a first set of bridges, wherein the first set of bridges is coupled to a first set of inductors; 
 a second power supply rail to provide a second power supply as input to a second set of bridges, wherein the second set of bridges is coupled to a second set of inductors; and 
 a controller to monitor electrical characteristics associated with the first and second power supply rails, and to control one or more switches to substantially balance power received by the first and second set of bridges, wherein the one or more switches are coupled to the first and second bridges and the first and second power supply rails, and wherein the controller is to close the one or more switches to move a phase of a bridge of the first set of bridges to the second set of bridges if the second set of bridges demands less power from the second power supply rail than the first set of bridges demand from the first power supply rail. 
 
     
     
       2. The apparatus of  claim 1 , wherein an individual bridge of the first set of bridges is to provide a first phase to a load, wherein an individual bridge of the second set of bridges is to provide a second phase to the load, and wherein the first phase is different from the second phase. 
     
     
       3. The apparatus of  claim 2 , wherein the load is a system-on-chip. 
     
     
       4. The apparatus of  claim 1 , wherein the controller is to adjust a duty cycle of a drive signal to each bridge of the first and/or second set of bridges to introduce current inequality between the bridges. 
     
     
       5. The apparatus of  claim 4 , wherein the current inequality between the first and second set of bridges is introduced in response to measured input power. 
     
     
       6. The apparatus  1 , wherein the controller comprises:
 a first analog-to-digital converter coupled to a first resistor between the first power supply rail and the first set of bridges, wherein the first analog-to-digital converter is to receive a first voltage of the first power supply rail and a first current through the first power supply rail towards the first set of bridges. 
 
     
     
       7. The apparatus of  claim 6 , wherein the controller further comprises:
 a second analog-to-digital converter coupled to a second resistor between the second power supply rail and the second set of bridges, wherein the second analog-to-digital converter is to receive a second voltage of the first power supply rail and a second current through the second power supply rail towards the second set of bridges. 
 
     
     
       8. The apparatus of  claim 1 , further comprising:
 a first power sensor to measure a first power through the first power supply rail; and 
 a second power sensor to measure a second power through the second power supply rail. 
 
     
     
       9. The apparatus of  claim 8 , wherein the controller comprises:
 a first analog-to-digital converter coupled to an output of the first power sensor, 
 wherein the first analog-to-digital converter is to convert the measured first power to a first digital representation of the measured first power; and 
 a second analog-to-digital converter coupled to an output of the second power sensor, wherein the second analog-to-digital converter is to convert the measured second power to a second digital representation of the measured second power. 
 
     
     
       10. The apparatus of  claim 8 , further comprising a node to sum the measured first and second powers, and provide the sum to the controller. 
     
     
       11. The apparatus of  claim 8 , further comprising:
 a first comparator to compare the measured first power with a first reference power; 
 a second comparator to compare the measured second power to a second reference power; and 
 an OR gate to perform an OR logic function with outputs of the first and second comparators, wherein an output of the OR gate is provided to a load. 
 
     
     
       12. A system comprising:
 a first set of inductors; 
 a first power supply rail to provide a first power supply as input to a first set of bridges, wherein the first set of bridges is coupled to the first set of inductors; 
 a second set of inductors; 
 a second power supply rail to provide a second power supply as input to a second set of bridges, wherein the second set of bridges is coupled to the second set of inductors; 
 a system-on-chip coupled to the first and second set of inductors; 
 one or more switches are coupled to the first and second set of bridges and the first and second power supply rails; and 
 a voltage regulator (VR) controller to monitor electrical characteristics associated with the first and second power supply rails, and to dynamically control the one or more switches to substantially balance power received by the first and second set of bridges, wherein the VR controller is to close the one or more switches to move a phase of a bridge of the first set of bridges to the second set of bridges if the second set of bridges demands less power from the second power supply rail than the first set of bridges demand from the first power supply rail. 
 
     
     
       13. The system of  claim 12 , wherein the VR controller is to adjust a duty cycle of a drive signal to each bridge of the first and/or second set of bridges to balance current flow through the bridge. 
     
     
       14. The system of  claim 12 , wherein an individual bridge of the first set of bridges is to provide a first phase to a load, wherein an individual bridge of the second set of bridges is to provide a second phase to the load, and wherein the first phase is different from the second phase. 
     
     
       15. An apparatus comprising:
 a first power supply rail to provide a first power supply as input to a first set of bridges, wherein the first set of bridges is coupled to a first set of inductors; 
 a second power supply rail to provide a second power supply as input to a second set of bridges, wherein the second set of bridges is coupled to a second set of inductors; 
 a controller to monitor electrical characteristics associated with the first and second power supply rails, and to control one or more switches to substantially balance power received by the first and second set of bridges, wherein the one or more switches are coupled to the first and second bridges and the first and second power supply rails; 
 a first power sensor to measure a first power through the first power supply rail; 
 a second power sensor to measure a second power through the second power supply rail; and 
 a node to sum the measured first and second powers, and provide the sum to the controller. 
 
     
     
       16. The apparatus of  claim 15 , wherein an individual bridge of the first set of bridges is to provide a first phase to a load, wherein an individual bridge of the second set of bridges is to provide a second phase to the load, and wherein the first phase is different from the second phase. 
     
     
       17. The apparatus of  claim 16 , wherein the load is a system-on-chip. 
     
     
       18. The apparatus  15 , wherein the controller comprises:
 a first analog-to-digital converter coupled to a first resistor between the first power supply rail and the first set of bridges, wherein the first analog-to-digital converter is to receive a first voltage of the first power supply rail and a first current through the first power supply rail towards the first set of bridges. 
 
     
     
       19. The apparatus of  claim 18 , wherein the controller further comprises:
 a second analog-to-digital converter coupled to a second resistor between the second power supply rail and the second set of bridges, wherein the second analog-to-digital converter is to receive a second voltage of the first power supply rail and a second current through the second power supply rail towards the second set of bridges. 
 
     
     
       20. An apparatus comprising:
 a first power supply rail to provide a first power supply as input to a first set of bridges, wherein the first set of bridges is coupled to a first set of inductors; 
 a second power supply rail to provide a second power supply as input to a second set of bridges, wherein the second set of bridges is coupled to a second set of inductors; 
 a controller to monitor electrical characteristics associated with the first and second power supply rails, and to control one or more switches to substantially balance power received by the first and second set of bridges, wherein the one or more switches are coupled to the first and second bridges and the first and second power supply rails; 
 a first power sensor to measure a first power through the first power supply rail; 
 a second power sensor to measure a second power through the second power supply rail; 
 a first comparator to compare the measured first power with a first reference power; 
 a second comparator to compare the measured second power to a second reference power; and 
 an OR gate to perform an OR logic function with outputs of the first and second comparators, wherein an output of the OR gate is provided to a load. 
 
     
     
       21. The apparatus of  claim 20 , wherein an individual bridge of the first set of bridges is to provide a first phase to a load, wherein an individual bridge of the second set of bridges is to provide a second phase to the load, and wherein the first phase is different from the second phase. 
     
     
       22. The apparatus of  claim 21 , wherein the load is a system-on-chip. 
     
     
       23. The apparatus  20 , wherein the controller comprises:
 a first analog-to-digital converter coupled to a first resistor between the first power supply rail and the first set of bridges, wherein the first analog-to-digital converter is to receive a first voltage of the first power supply rail and a first current through the first power supply rail towards the first set of bridges. 
 
     
     
       24. The apparatus of  claim 23 , wherein the controller further comprises:
 a second analog-to-digital converter coupled to a second resistor between the second power supply rail and the second set of bridges, wherein the second analog-to-digital converter is to receive a second voltage of the first power supply rail and a second current through the second power supply rail towards the second set of bridges.